ORIGINAL PAPER

Mortality in a cardiac intensive care unit

Carsten Zobel • Marcus Dorpinghaus •

Hannes Reuter • Erland Erdmann

Received: 20 July 2011 / Accepted: 26 January 2012 / Published online: 9 February 2012

� Springer-Verlag 2012

Abstract

Objective There are no reliable data on mortality and

morbidity of adult patients in modern university-based

cardiac intensive care units. Therefore, the present study

was aimed to provide complete data in respect to mortality

and morbidity of all patients admitted between 1 January

2008 and 31 December 2009 to the newly opened cardiac

intensive care unit of the Heart Centre of the Cologne

University Hospital.

Methods All patients admitted to the 6-bed intensive care

unit of the Heart Centre of the University of Cologne

between January 1 2008 and December 31 2009 were

included in this study.

Results A total of 684 patients were investigated. The

majority of patients (71.1%) were male. The overall in-

hospital mortality was 32.5%. The most frequent diagnosis

was acute coronary syndrome (43.6%). Coronary angiog-

raphy was performed in 45.5% of all patients. Cardiopul-

monary resuscitation was the reason for admission in

30.8%, the in-hospital mortality of those patients (46.0%)

was much higher compared to the overall mortality.

Conclusions Our data demonstrate that despite state-of-

the-art university-based intensive care medicine with

modern equipment the mortality remains high. These

findings will help in calculating the resources required to

meet the increasing demand for intensive care medicine.

Keywords Intensive care medicine � Mortality �Cardiovascular disease � Morbidity

Introduction

In modern societies a continued longer life expectancy is

seen, with the proportion of individuals aged 60 years or

more growing faster than any other age group. Furthermore,

cardiovascular disease has become the most important cause

of morbidity and mortality in industrialized countries,

resulting in increasing demands for cardiologic intensive

care treatment. However, little is known about the true

mortality and morbidity of patients in modern university-

based cardiac intensive care units (ICUs). An intensive lit-

erature search did not reveal any data that would include all

consecutive patients from a single unit. The present study,

therefore, was aimed to provide complete data in respect to

mortality and morbidity of all patients admitted between

1 January 2008 and 31 December 2009 to the newly opened

cardiac intensive care unit of the Heart Centre of the Cologne

University Hospital.

Methods

The study was conducted in a 6-bed intensive care unit of

the Clinic for Internal Medicine (cardiology, angiology,

pneumology and internal intensive care medicine) at the

Heart Centre of the University of Cologne. The majority of

the patients were admitted through the emergency medical

services of the city of Cologne. Since our Centre also has

an 18-bed intermediate care unit (not equipped for venti-

lation of patients and with less nursing and resident staff)

only severely ill patients were treated in the intensive care

unit. All patients admitted to the intensive care unit

between January 1 2008 and December 31 2009 were

included in the study. The Acute Physiology and Chronic

Health Evaluation (APACHE) IV [5] score was calculated

C. Zobel (&) � M. Dorpinghaus � H. Reuter � E. Erdmann

Department of Internal Medicine III,

University of Cologne, 50924 Cologne, Germany

e-mail: carsten.zobel@uk-koeln.de

123

Clin Res Cardiol (2012) 101:521–524

DOI 10.1007/s00392-012-0421-9

based on patient demographics, admission source, primary

admission diagnosis, and detailed laboratory and physio-

logic variables collected in the first 24 h of ICU admission.

Patients admitted after successful cardiopulmonary resus-

citiation always underwent acute coronary angiography

following our standard operating procedures. Mild thera-

peutic hypothermia was already initiated by the emergency

physician by means of cooled infusions and was then

continued by insertion of a cooling catheter for 24 h after a

temperature of 33�C was achieved. Standard operating

procedures for the most common diseases and procedures

are established. The study complies with the Declaration of

Helsinki. The institutional review board waived the need

for informed consent since this was an epidemiological

study.

Statistics

All statistical tests were two-tailed, and a significance level

of p = 0.05 or less was used. Descriptive statistics inclu-

ded mean and SD values except when otherwise stated.

Students’s t test was used for comparisons of means of

continuous variables and normally distributed data. Cate-

gorical data were tested using the Chi square statistics

(Table 1).

Results

A total of 684 patients were admitted to the unit and were

included. The majority of patients (71.1%) were male. The

Table 1 Demographic data of

the study population

* p \ 0.01 versus survivors

All

(n = 684)

Survivors

(n = 462)

Non-survivors

(n = 222)

Age (years) 66.3 ± 13.8 65.2 ± 13.9 68.6 ± 13.3*

Gender male, n (%) 486 (71.1) 333 (68.5) 153 (31.5)

Age (years) 65.3 ± 13.1 64.2 ± 12.9 67.7 ± 13.1*

Gender female, n (%) 198 (28.9) 129 (65.2) 69 (34.8)

Age (years) 68.8 ± 15.3 67.7 ± 16.1 70.7 ± 13.5

ICU stay (days) 4.91 ± 8.5 5.2 ± 9.22 4.4 ± 6.8

Diagnostic categories n (%)

Acute coronary syndrome 298 (43.6) 191 (64.1) 107 (35.9)

STEMI 204 (29.8) 125 (61.3) 79 (38.7)

NSTEMI 63 (9.2) 41 (65.1) 22 (34.9)

Unstable angina pectoris 31 (4.5) 25 (80.6) 6 (19.4)

Arrhythmia 103 (15.3) 78 (75.7) 25 (24.3)

Resuscitation 211 (30.8) 114 (54.0) 97 (46.0)

Cardiogenic shock 159 (23.2) 66 (41.5) 93 58.8)

ECMO 4 (0.6) 1 (25.0) 3 (75.0)

IABP 26 (3.8) 9 (34.6) 17 (65.4)

Acute decompensated heart failure 100 (14.6) 74 (74.0) 26 (26.0)

Valvular disease 43 (6.3) 28 (65.1) 15 (34.9)

Aortic stenosis 43 (6.3) 16 (69.6) 7 (30.4)

Endocarditis 12 (1.8) 6 (50.0) 6 (50.0)

Sepsis 37 (5.4) 20 (54.1) 17 (45.9)

Malignancy 25 (3.7) 20 (80) 5 (20)

Pulmonary disease 22 (3.2) 16 (72.7) 6 (27.3)

Pulmonary embolism 12 (1.8) 6 (50) 6 (50)

Aortic dissection 9 (1.3) 3 (33.3) 6 (66.7)

Other 35 (5.1) 26 (74.3) 9 (25.7)

Risk factors n (%)

Hypertension 334 (48.8) 246 (73.7) 88 (26.3)

Diabetes 165 (24.1) 112 (67.9) 53 (32.1)

Renal insufficiency 288 (42.1) 187 (64.9) 101 (35.1)

SLEDD 94 (13.7) 42 (44.7) 52 (55.3)

522 Clin Res Cardiol (2012) 101:521–524

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ICU mortality was 27.8%, the in-hospital mortality was

32.5%, with little difference between male (30.9%) and

female patients (33.5%, p = 0.394). Of the 222 patients

with fatal outcome 51.8% died during the first 48 h and

36.0% during the first 12 h. 56.1% of patients were

mechanically ventilated. The mortality of ventilated

patients was significantly higher compared to the non-

ventilated patients (44.8%, p \ 0.001). We calculated the

APACHE-IV [5] score to provide an estimate of the

average disease severity of the patients. The score could

not be calculated for 135 patients whom had a length of

stay on the ICU below 4 h. The expected overall hospital

mortality was 37% which was slightly higher than the true

mortality of 32.5% (which included also patients with a

length of stay below 4 h).

The average age of all patients was 66.3 (15–99) years.

The survivors were slightly younger [65.3 (17–99) years]

compared to the patients who died [68.6 (15–95) years,

p = 0.002]. In the group of patients between 30 and

80 years the number of male patients was more than twice

as high as the number of female patients (Fig. 1). In the

groups younger than 30 years or older than 80 years the

number of female and male patients was similar.

43.6% of the patients had an acute coronary syndrome

(ACS) with cardiopulmonary instability or cardiogenic

shock as primary diagnosis. Of these patients the majority

(68.5%) had ST elevating myocardial infarction (STEMI),

21.1% were suffering form non-ST elevating myocardial

infarction (NSTEMI) and 10.5% were patients with

unstable angina pectoris. The mortality of patients with

ACS was close to the overall mortality with 35.9%

(p = 0.216). Cardiopulmonary resuscitation was the reason

for admission to the intensive care unit in 30.8% of all

cases, the in-hospital mortality of those patients was higher

compared to the average mortality with 46.0% (p \ 0.001).

The highest relative mortality (66.7%, p \ 0.005) was

observed in patients with aortic dissection followed by

patients with pulmonary embolism (50%, p \ 0.005) and

sepsis as main diagnosis (45.9%, p \ 0.005).

Coronary angiography was performed in 45.5% of all

patients. In 44.7% of the procedures patients underwent a

percutaneous coronary intervention with placement of one

or more stents. Mortality in patients without stent place-

ment was significantly higher (35.5%, p = 0.01) compared

to those who received at least one stent (25.2%).

Diabetes mellitus was recoded in 24.1% of all patients

and 42.1% were suffering from renal failure.

Discussion

The in-hospital mortality of patients treated in a university-

based cardiac intensive care unit was 32.5%. A literature

search regarding the mortality in comparable ICUs with

similar patient characteristics revealed only one study from

the year 2000. Janssens et al. [2] reported an in-hospital

mortality of 14.5%, however, patients with an ICU stay

shorter than 12 h were excluded from the analysis, which

imposes a major bias since mortality in the first 12 h is

extremely high for patients with life threatening cardiac

disease. Of the 222 patients with fatal outcome in our

investigation 80 (36.0%) died during this period. The

presence of an intermediate care unit in the Heart Centre of

the University of Cologne might also have contributed to

the higher mortality since less severely diseased patients

with presumably better outcome were treated there. This

fact is also the most likely explanation for the high ACS

mortality of 35.9%. The large excess of male patients

between the age of 30 and 80 years seems surprising since

the German age pyramid [1] shows a slightly higher

number of males only up to the age of 55 years whereas

women prevail considerably in older age groups. This

phenomenon has recently been addressed in a multiple

centre cohort study [4]. The authors suggested that a gen-

der-related bias in the clinical decision-making process

may contribute to the excess of male patients on intensive

care units. Zimmermann et al. [6] reported that of 566

patients admitted with STEMI from 1999 to 2006 only 161

(28.4%) were females. Female patients were on average

8 years older than men, had higher co-morbidity [3, 6] and

the pre-hospital delay from symptom onset to admission

was significantly longer. Corresponding with our observa-

tion women did not have a significantly higher mortality

0

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Non-Survivor

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Num

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Age and sex

Fig. 1 Age distributions and mortality in women and men. The figure

shows the proportion of male and female patients as well as the

corresponding mortality in various age groups. (ECMO extracorporal

membrane oxygenation, IABP intraaortic ballon pump, SLEDDsustained low-efficiency daily diafiltration)

Clin Res Cardiol (2012) 101:521–524 523

123

rate despite their more advanced age and the higher prev-

alence of co-morbidities.

Our findings demonstrate that despite highly sophisti-

cated university-based intensive care medicine the mor-

tality is surprisingly high. The presented data might help in

the planning process for the increasing demands of critical

care medicine driven by an aging population with a greater

number of disease comorbidities, increasing therapeutic

complexity and greater healthcare expectations in the

future.

Conflict of interest None.

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303 consecutive patients with predominantly cardiovascular dis-

orders. Sequential organ failure assessment. Intensive Care Med

26:1037–1045

3. Koeth O, Zahn R, Heer T, Bauer T, Juenger C, Klein B, Gitt AK,

Senges J, Zeymer U (2009) Gender differences in patients with

acute ST-elevation myocardial infarction complicated by cardio-

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Gender-related differences in intensive care: a multiple-center

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FA (2009) Short-term prognosis of contemporary interventional

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